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A kind of phosgene removal method of m-xylylene diisocyanate

A technology of m-xylylene diisocyanate and phosgene, which is applied in the field of phosgene removal of m-xylylene diisocyanate, can solve problems such as difficult removal of phosgene, improve safety and reduce consumption The effect of volume and load reduction

Active Publication Date: 2020-11-13
QINGDAO UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The novelty of the present invention is that the phosgene removal tower adopts a negative pressure operating system, which solves the difficult problem of m-xylylene diisocyanate phosgene removal

Method used

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  • A kind of phosgene removal method of m-xylylene diisocyanate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The mixed solution of amine and o-dichlorobenzene with a concentration of 4.8% and a flow rate of 1000 kg / h and phosgene with a temperature of -10°C and a flow rate of 278 kg / h are carried out in photochemical reactor 1 for cold-hot photochemical reaction. The HCL gas and excess phosgene produced after photochemical pass into the phosgene recovery system; the reacted photochemical liquid contains XDI, o-dichlorobenzene, phosgene and HCL, its temperature is 138℃, and the flow rate is 1481kg / h. The phosgene content is 2.5% and the isocyanate content is 4.0%. The photochemical liquid discharge pump 6 is continuously fed into the phosgene removal tower 2 for rectification. The operating pressure of the phosgene removal tower 2 is -0.2barg; The mixed gas such as solvent and phosgene from the top of tower 2 enters the first-stage condenser 4 at the top of the tower, and its temperature is controlled at 40°C; the uncondensed gas enters the second-stage condenser 5 at the top of ...

Embodiment 2

[0025] The mixed solution of amine and o-dichlorobenzene with a concentration of 4.8% and a flow rate of 1000kg / h and phosgene with a temperature of -10°C and a flow rate of 278kg / h are carried out in photochemical reactor 1 for cold-hot photochemical reaction. The HCL gas and excess phosgene produced after photochemical pass into the phosgene recovery system; the reacted photochemical liquid contains XDI, o-dichlorobenzene, phosgene and HCL, its temperature is 138℃, and the flow rate is 1481kg / h. The phosgene content is 2.5% and the isocyanate content is 4.0%. The photochemical liquid discharge pump 6 is continuously passed into the phosgene removal tower 2 for rectification. The operating pressure of the phosgene removal tower 2 is -0.1barg; The mixed gas such as solvent and phosgene from the top of tower 2 enters the first-stage condenser 4 at the top of the tower, and its temperature is controlled at 30°C; the uncondensed gas enters the second-stage condenser 5 at the top of...

Embodiment 3

[0027] The mixed solution of amine and o-dichlorobenzene with a concentration of 4.8% and a flow rate of 1000kg / h and phosgene with a temperature of -10°C and a flow rate of 278kg / h are carried out in photochemical reactor 1 for cold-hot photochemical reaction. The HCL gas and excess phosgene produced after photochemical pass into the phosgene recovery system; the reacted photochemical liquid contains XDI, o-dichlorobenzene, phosgene and HCL, its temperature is 139℃, and the flow rate is 1481kg / h. The phosgene content is 2.5% and the isocyanate content is 4.0%. The photochemical liquid discharge pump 6 is continuously passed into the phosgene removal tower 2 for rectification. The operation pressure of the phosgene removal tower 2 is -0.5barg; The mixed gas such as solvent and phosgene from the top of tower 2 enters the first-stage condenser 4 at the top of the tower, and its temperature is controlled to 50℃; the uncondensed gas enters the second-stage condenser 5 at the top of ...

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Abstract

The invention discloses a method for removing phosgene from isophthalylidene diisocyanate. The method includes the steps that isophthalylidene diisocyanate (XDI) actinic solution containing a high-boiling-point solvent enters a phosgene removal tower of a negative-pressure operation system, the temperature of the tower is adjusted to be proper to remove residue phosgene, then the temperature of atower top condenser is adjusted to condense the tower top solvent, the phosgene and other mixed gas at the same time, the phosgene is reduced as much as possible or prevented from entering a vacuum system, and tower top condensate serves as an absorbing agent to be used for a phosgene recycling system. The method is suitable for removing the phosgene by using the high-boiling-point solvent and theXDI with a heat sensitivity problem or similar isocyanate. The method is high in phosgene removing capacity, reduces the load of the vacuum system, reduces the consumption of a cryogenic medium, andomits the process that parts of solvents are specially removed to be used for the phosgene recycling system.

Description

Technical field [0001] The invention belongs to the technical field of negative pressure phosgene removal, and relates to a phosgene removal method of m-xylylene diisocyanate. Background technique [0002] M-xylylene diisocyanate (XDI) has a benzene ring, and its two NCO groups are connected to the benzene ring through a methylene group, so that the gap between the methylene groups prevents the NCO group from interacting with benzene. The ring resonates and does not cause yellowing of polyurethane products. XDI is mainly used to prepare outdoor polyurethane materials, such as coatings, adhesives, elastomers and other non-yellowing polyurethane products. The preparation method of XDI is mainly the liquid phase phosgenation method, and the generated photochemical liquid needs to remove phosgene before proceeding to the next production process. Traditional phosgene removal methods include pressure or atmospheric distillation to remove phosgene, and nitrogen purge to remove phosgen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C263/10C07C263/20C07C265/14
CPCC07C263/10C07C263/20C07C265/14
Inventor 毕荣山谭心舜郑世清曾民成葛纪军
Owner QINGDAO UNIV OF SCI & TECH
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